I believe that camp scene only happens as a follow-up to seeing the first 'hand' scene, could be wrong there.

As for why you take children, easier to condition, large meme below. We know Thorm was leeching off the village for at least a little while before he revealed himself.
[Linked Image from i.redd.it]

As for the webs in the Necromancer's lab, I can't say, spiders get around? Though that one spider egg object you find in the Harper lookout has had my head spinning for a while now, It's got to mean something right?

From everything we're finding, did the Justiciar conflict happen around 30 years ago? Where do we get a timeline for that? GM4Him says 1371 but I'm not sure where that comes from. At this point I'm wondering of the Cult in BG is made up of the refugees from Moonrise, such as the stolen children, Half-Elves live slightly longer than humans...I'm not sure if SH fits in well there, especially if the interlude is from 1371 - 1492